The present invention relates generally to wireless telephones, and more particularly, to adapters that power a wireless telephone for use in a vehicle.
An adapter is required to run the wireless telephone off of the vehicle electrical power rather than the telephone battery. The present invention is directed to an adapter for a wireless telephone that utilizes a solderless one-piece ground contact.
The prior art describes a number of adapters that permit operation of various electronic devices from the electrical power source of a vehicle. These adapters all share certain common components. Each adapter must have a xe2x80x9chotxe2x80x9d contact that is connected to the vehicle xe2x80x9chotxe2x80x9d source of power, and each adapter must have a xe2x80x9creturnxe2x80x9d or xe2x80x9cgroundxe2x80x9d contact that is connected to the ground of the vehicle.
Some of these adapters utilize internal circuit boards and have their ground contacts connected directly to the circuit board, such as by soldering. The soldered joint may be positioned on the circuit board in an area where it undergoes great stress, inasmuch as the adapter ground contacts are typically themselves compressed when inserted into a cigarette lighter receptacle. Other ground contacts are not soldered to the circuit board, but rather are disposed in the adapter housing such that at least one interconnecting wire may be soldered thereto for opposite termination of the interconnecting wire at a remote circuit board or wire by soldering or other means. The ground contacts are positioned in such a manner that any contact forces exerted by the contacts on the adapter circuit board balance each other so as not to apply any detrimental, unbalanced stress to the circuit board or other part of the adapter. One-piece contact arms have also been utilized with cigarette lighter adapters which may or may not have a circuit board disposed inside the adapter. Those which do not have a circuit board use a wire and solder solution to connect the ground contact to the vehicle ground system. In an adapter which has a circuit board, the ground contact engages only one side of the circuit board in an undisclosed manner.
Accordingly, it is a general object of the present invention to provide an improved adapter for connection of a wireless telephone to a source of electrical power in a vehicle.
Another object of the present invention is to provide an adapter for connecting a wireless telephone to a vehicle""s cigarette lighter receptacle, wherein the adapter has an internal circuit board containing charging and connection circuits, and a ground contact that connects the circuit ground to the vehicle ground, wherein the ground contact engages the circuit board in a solderless connection.
Still another object of the present invention is to provide a cigarette lighter adapter that provides an electrical connection between a cigarette lighter of a vehicle and a wireless telephone, the adapter having a charging and connection circuit disposed on a circuit board held within an adapter housing, the adapter having a ground contact in the form of a one-piece spring member having clip legs in confronting relationship to each other and to a common point on the circuit board, the clip legs exert substantially equal contact forces on the circuit board when the adapter is inserted into the vehicle cigarette lighter receptacle.
Yet another object of the present invention is to provide a cigarette lighter adapter for a wireless telephone which has less parts and is easier to manufacture and less expensive.
These objects are accomplished by at least one principal aspect of the present invention in which the adapter has a housing for relevant components. The housing contains a circuit board therein. The circuit board has a ground circuit defined therein on with one or more contact pads. A resilient spring member is provided as a ground contact and is held within the adapter housing having a portion of the ground contact in opposition to the ground circuit contact pad(s). The spring member may contact the ground circuit contact pad(s) and is forced into further contact therewith when the ground contact becomes compressed during insertion of the adapter into a cigarette lighter receptacle.
In another principal aspect of the present invention, the ground contact takes the form of a U-shaped clip, with each clip leg having a contact arm that extends therefrom and over the clip. The U-shaped clip is associated with the circuit board contact pad(s) such that the circuit board is received between the legs of the U-shaped clip. The contact arms are positioned within the adapter in opposition to each other so that the contact forces that they exert on the circuit board whether the adapter is in or out of a cigarette lighter receptacle, substantially balance each other so as not to apply the detrimental stress to the circuit board.
These and other objects, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, wherein like reference numerals refer to like parts.